Members of the Department of Neurosciences at the School of Medicine are currently conducting PHS funded clinical and basic research programs concerning the mechanisms and treatment of degenerative central nervous system diseases including Alzheimer's disease, Parkinsonism, epilipsy as well as studies of normal aging. A major aspect of these studies involves neurotransmitter, neuropeptide, amino acid, and drug analyses using high-performance liquid chromatography, electrochemical detection (HPLC-EC) instrumentation. The majority of assays have been provided through collaborative arragnements with investigators at nearby institutions. Current and future human and animal model studies, however, involve larger numbers of samples and the need to measure other important neurochemical or drug substances, thus rendering these collaborative arrangements impractical and inadequate. The need exists for an instrument with superior analytical resolution to accurately assay complex biological tissues (e.g., human brain, CSF, and plasma) and at the same time be able to process large numbers of samples. The Neurochem Neurochemical Analyzer (NCA), an HPLC-EC instrument recently developed by ESA, Inc. uniquely fulfills these criteria. Funds are requested to purchase the NCA to serve as a departmental "core" apparatus for the shared use of its funded investigators. Unlike other HPLC-EC systems, the NCA combines: i) a superior analytical resolution through its unique array of 16 electrochemical detectors; ii) capability of quantifying over 80 compounds in a single 45 mins run; iii) high volume capacity through its refrigerated 100 sample autosampler and computer driven, 24 hr (overnight) unattended operation; and iv) routine sensitivity in the mid femtogram (5 X 10-13) range. A five member internal advisory board will oversee its use. During the first two years the three major user will utilize 100% of this instrument's time based on a 24 hr, five day work week. In subsequent years, as time becomes available, eight other departmental investigators will be permitted to use this instrument for neurochemical analyses involved in their research projects. The PI has extensive experience in the development of analytical methods using HPLC-EC instruments and will train and supervise the users' technicians in the operation and use of the NCA.